#include<stdio.h>
int main()
{
	int m,t,s,sum;
	scanf("%d%d%d",&m,&t,&s);
	if(t==0) 
	{
		printf("0");
		return 0;
	}
	else
	if(s%t!=0)
	sum=m-s/t-1;
	else
	sum=m-s/t;
	sum<=0?printf("0"):printf("%d",sum);
    return 0;
}

